This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present disclosure. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present invention. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
Hydrocarbons are generated in the subsurface from source rocks rich in organic matter. Following initial deposition, source rocks are buried and subjected to increasing temperature and pressure with increasing burial. Hydrocarbons are generated when the source rocks reach temperatures sufficient for the thermal conversion of organic material to kerogen and then to free liquid and/or gaseous hydrocarbon phases, which is a process called source rock maturation. Upon generation, the hydrocarbons may subsequently be expulsed from the source rock and migrate in the subsurface to reservoir rocks (such as sandstones or limestones) that have sufficient porosity, structure and an adequate seal that make them capable of trapping the hydrocarbon phase(s), allowing hydrocarbons to accumulate. Alternatively, hydrocarbons may migrate to a surface location (e.g., sometimes referred to as a seep). Any hydrocarbons present in the subsurface may be preserved or they may be subjected to different forms of alteration. For example, biodegradation is the process of degradation or consumption of hydrocarbons by micro-organisms. Similarly, hydrocarbons may be thermally altered by exposure to temperatures above their thermal stability. Alternatively, hydrocarbons may be oxidized or consumed in processes, such as thermochemical sulfate reduction. In addition to hydrocarbons, non-hydrocarbon compounds (e.g., carbon dioxide CO2, carbon monoxide CO, nitrogen N2, hydrogen sulfide H2S, helium He, neon Ne, argon Ar, krypton Kr, and xenon Xe) may also be present alongside hydrocarbons in subsurface accumulations. The concentration and isotopic signature of these compounds may be inherited from contact with formation waters, from mixing and interaction with other fluids in the subsurface (e.g. hydrothermal fluids, magmatic fluids) or from processes that liberate these compounds from rocks and minerals in the subsurface. Each of these processes from generation to storage and alteration influences the geochemical signature of these hydrocarbons and associated non-hydrocarbon compounds and gives rise to combined geochemical signatures that record a history of where these compounds originated and what processes they have experienced.
Evaluating and monitoring well performance, fracking and stimulation efficiency, reservoir drainage and overall production effectiveness can be challenging. Conventional tools include production logging tests, which can be costly; pressure monitoring, which may not capture full fluid flow; and tracer addition operations, which may be ineffective for tight reservoirs. Monitoring of geochemical variations on a production time-scale (e.g., time-lapse geochemistry) can be utilized, but generally does not provide advantages to the analysis if the geochemical variation between fluids from different reservoirs is slight or if there are few geochemical components to monitor (e.g., gas reservoirs).
There remains a need in the industry for apparatus, methods, and systems to identify and enhance hydrocarbon operations. In particular, conventional techniques do not properly distinguish and/or provide accurate quantitative estimates between the amount of hydrocarbon compounds (e.g., gas or liquid) that is adsorbed onto sediments in the subsurface and the amount of hydrocarbon compounds present as a free phase or between fracture and matrix derived fluids. Further, conventional techniques do not provide effective tools that can address questions relating to the extent of fracture penetration, identify wellbore integrity concerns, and accurately determine the production fetch area for a given producing well.